Blocking Back 3-3 on LNER

[ColHut]

Dear All,

 

I am having trouble with the LNER double line block signalling regulations.

 

A copy is here:

 

http://www.ekeving.se/ext/uk/BlockReg/AB%20LNER%201950.pdf

 

The attached extract (omitting 13(d)&(e) ) is below:

 

 

 

The regs. state:

NOTES.— (i) This Clause (a) does not apply where Outer Home Signals are provided.

...

 

(c ) When a Signalman asks permission to occupy the line outside his Home Signal (or Home Signal next in advance of an Outer Home Signal), he must give the Blocking Back signal (3-3) to the Signalman at the box in rear. 

 

It seems where an outer home is provided the 2-4 and 4-2 are not used.

 

Instead if blocking the line between the outer and inner home, or outside the outer home, then 3-3 is used, (and there are additional restriction on reg.5).  

 

If operating in rear of his inner home then he s free to go about his business.  Depending upon the actual distances between his outer and inner home, if more than 1/4 mile, he might be able to accept a train under Reg 4 as well.

 

Did I get this right?

 

regards

Edited February 16, 2018 by ColHut

[bécasse]

Acceptance under regulation 5 only applied where it was specially authorised (in the Special Instructions of the two boxes concerned) and in all the cases I personally have come across it was authorised because there was no outer home*. The railway being the railway there were probably exceptions to this but the rules for such cases would have been laid down in the Special Instructions rather than the more general Regulations. An important point about Special Regulations is that they applied only to the signalmen concerned and whatever was done as a result had to appear to train crews as a normal procedure - so acceptance into a block section under the warning arrangement would indicate to the train crews that they had to approach the next stop signal (be it home or, unusually, outer home) with particular care as the line immediately beyond it might be blocked.

 

* A very common place to find regulation 5 acceptance being permitted was around the sides of triangles where there was no space to provide outer homes.

 

Edited to correct references to regulation 4 (incorrect) to regulation 5 (correct)!

Edited February 16, 2018 by bécasse

[ColHut]

Did you mean reg 5 in the above regs?  Reg 4 is the normal line clear acceptance. 

[The Stationmaster]

Dear All,

 

I am having trouble with the LNER double line block signalling regulations.

 

A copy is here:

 

http://www.ekeving.se/ext/uk/BlockReg/AB%20LNER%201950.pdf

 

The attached extract (omitting 13(d)&(e) ) is below:

 

 

13.jpg

 

The regs. state:

NOTES.— (i) This Clause (a) does not apply where Outer Home Signals are provided.

...

 

(c ) When a Signalman asks permission to occupy the line outside his Home Signal (or Home Signal next in advance of an Outer Home Signal), he must give the Blocking Back signal (3-3) to the Signalman at the box in rear. 

 

It seems where an outer home is provided the 2-4 and 4-2 are not used.

 

Instead if blocking the line between the outer and inner home, or outside the outer home, then 3-3 is used, (and there are additional restriction on reg.5).  

 

If operating in rear of his inner home then he s free to go about his business.  Depending upon the actual distances between his outer and inner home, if more than 1/4 mile, he might be able to accept a train under Reg 4 as well.

 

Did I get this right?

 

regards

 

The LNER Regulations were rather unusual in respect of Blocking Back (or to be more precise the Regulations for  this particular section of the LNER were unusual although it is likely that the other sections were similar - having not seen any examples for other sections I don't know if they were similar to these).

 

I suspect the Regulations had rather 'grown like Topsy' and the addition of Outer Home Signals had come along almost as an afterthought and had either not then been fully thought through or maybe it was decided to apply belt & bracest.   Logically with a properly sited Outer Home Signal at least 440 yards in rear of the Home Signal that made the Home Signal the Clearing Point and therefore there was no need for a 2-4 Block Back because the Clearing Point was not fouled.  The key point thus far is that what the 2-4 Block Back was about was physically fouling the Clearing Point in such a way that a train could not be accepted under full 'Line Clear' in accordance with Regulation 4.  

 

Sos far it all makes perfect sense and of course one of the main points on double line block about providing an Outer Home Signal was to allow things to take place in advance of the (now Inner) Home Signal while still being able to accept a train under full 'Line Clear' from the 'box in rear.

 

Where the LNER Regulation is unusual is requiring a 3-3 Block Back in respect of a shunt etc coming to a stand when set back in rear of the Home Signal if there is an Outer Home Signal because all that is happening is that the Clearing Point is being fouled, i.e. it is directly equivalent to a 2-4 Block Back on the other Companies or a 2-4 Block Back where there is no Outer Home Signal.   I can't understand why the Regulation is worded in that way as something coming to a stand etc between the Outer Home and the Home Signal is doing no more than fouling the Clearing Point which on all of the other three Grouped companies was covered by a 2-4 Block Back, the only time they applied a 3-3 Block Back was when the movement etc would set back in rear of the outermost Home Signal (which on some Companies would be called the Outer Home Signal).  And of course the 1960 (more or less) standard BR Block Regulations applied exactly the same principle as that previously used by the other three mainline Companies.

 

According to the explanatory notes issued with the 1960 Block Regulations the Regulations which had applied on GN and GC lines until then (presumably those you linked above) were amended to bring them into line with everyone else and it was specifically noted that a 3-3 Block Back would now apply outside the outermost Home Signal.  Not specifically stated in the notes was that a 2-4 Block Back also applied at the Outermost Home Signal so that might possibly have been altered in those particular LNER regulations between 1950 and 1960?

 

To answer your final If there is an outermost Home Signal at least 440 yards in rear of the next Home Signal in advance then a train could readily be accepted unless the section of line between those two signals is fouled by a stationary obstruction etc.  Always pays to remember (except in every case on the LNER) that the key thing about a 2-4 Block Back is it has to be sent before there is a stationary obstruction created within the Clearing Point.  On the LNER a 3-3 Block Back would be used if that obstruction was between the outermost Home Signal and the next stop signal in advance of it.

[bécasse]

Did you mean reg 5 in the above regs?  Reg 4 is the normal line clear acceptance. 

 

Sorry, I did indeed mean Regulation 5 Warning Arrangement, I have corrected the original post. It is a long time since I learnt "Rules & Regs" and almost as long since I last actually used the "Regs"!

[bécasse]

Following on to the Stationmaster's excellent explanation, IIRC the LNER added outer homes to help in coping with higher passenger train speeds on certain main lines. Where outer homes were added (rather than being part of the original signalling plan), there was a certain logic in retaining the use of the 3-3 blocking back arrangement for wrong road movements beyond the home (but within the new outer home) on a "what was 3-3, continues as 3-3" basis, even though the move now came within the protection of the box's own fixed signalling.

[micknich2003]

In comparison to the Former NERly Block Regulations, the LNERly new Regulations of c1934 were simplicity.

 The NERly Regulations contained a few "Unusual Bell Signals" , 3 2 1 and 1 2 3, Blocking Back for trains containg passengers, 4 2 Train arrived within Inner Home, 2 3 2 Has train reached signalbox?

If anyone is interested, I can post up the full details.

[ColHut]

Please do.

The old GNR 1897 Regs. did not use blocking back at all I think. I will post a link later.

 

https://archive.org/details/generalregulatio00grea_0

 

regards

Edited February 17, 2018 by ColHut

[ColHut]

Pigg J. discusses the general case in RAILWAY "BLOCK" SIGNALLING (1898).

 

https://ia800208.us.archive.org/4/items/cu31924031265824/cu31924031265824.pdf

 

regards

[micknich2003]

Col, I hope of interest. Yours, Mick.

 

[ColHut]

Thanks Mick,

 

Absolutely fascinating.

 

It certainly provides some context.

 

regards

[The Stationmaster]

In comparison to the Former NERly Block Regulations, the LNERly new Regulations of c1934 were simplicity.

 The NERly Regulations contained a few "Unusual Bell Signals" , 3 2 1 and 1 2 3, Blocking Back for trains containg passengers, 4 2 Train arrived within Inner Home, 2 3 2 Has train reached signalbox?

If anyone is interested, I can post up the full details.

 

On the GWR 1-2-3 was 'Blocking Back Outside Home Signal for a Train Already in Section'

 

Following on to the Stationmaster's excellent explanation, IIRC the LNER added outer homes to help in coping with higher passenger train speeds on certain main lines. Where outer homes were added (rather than being part of the original signalling plan), there was a certain logic in retaining the use of the 3-3 blocking back arrangement for wrong road movements beyond the home (but within the new outer home) on a "what was 3-3, continues as 3-3" basis, even though the move now came within the protection of the box's own fixed signalling.

 

I suspect that was indeed the case and it would be interesting to learn when it was incorporated in the LNER Block Regulations but it is certainly in the correct section of those Regulations for the ECML (and definitely does not seem to have been in at least on of the other sets of LNER 1934 Block Regulations.

 

Interestingly when I was told many years ago that when the accelerations were introduced a lot of double blocking (i.e. asking Line Clear through two successive sections due to inadequate braking distances from Distant Signals)) also had to be introduced and teh changes might well have been coincdent.

[Junctionmad]

didnt we flog this topic to death recently 

[ColHut]

Possibly it has been. For me, having no professional involvement in railways, least of all of the 1930s, I simply could not understand why the LNER seemed to do this differently. The oddity for the LNER is that it appears to permit blocking back in advance of an inner home without the 2-4 or 4-2 even if the inner home is not also a clearing point. And blocking back in rear of an inner home is treated the same as outside the home signal (3-3) instead of 2-4 or 4-2.

 

Answers are not obvious from looking at signal diagrams, especially without an understanding of the history and site limitations. Often this is lost in the mist of time. The apparently bizarre distances that stop signals appear from each other, without apparent regard for clearing points certainly adds to my confusion.

 

Thanks to the above I am better educated concerning the pre-grouping tensions and outer home additions which probably explains it.

 

regards